Close margin of adverse histologic factors with a negative primary tumor margin is not associated with increased locoregional recurrence in colon cancer.

Purpose: Locoregional recurrence after resection of colon cancer is increased when primary tumor margin is positive (<1 ​mm). Data is limited regarding the risk of locoregional recurrence with close margin (<1 ​mm) of histologic factors, such as intravascular tumor, intranodal tumor, tumor deposits, or extranodal extension. We hypothesized that close margin of these factors doesn't affect locoregional recurrence.

Acellular mucin in lymph nodes isolated from treatment-naïve colorectal cancer resections: a clinicopathologic analysis of 16 cases.

Lymph nodes with acellular mucin harvested from treated colorectal cancers (CRC) are staged as pN0. However, there is variability among pathologists while reporting the pN stage when acellular mucin is found within nodes of untreated CRCs. While the UICC guidelines suggest staging them as pN1, the AJCC and CAP do not offer any recommendations.

Distinguishing clear cell renal cell carcinoma, retroperitoneal paraganglioma, and adrenal cortical lesions on limited biopsy material: utility of immunohistochemical markers.

Retroperitoneal recurrence of clear cell renal cell carcinoma (CCRCC) after surgical resection is often investigated by needle biopsy and frequently requires immunohistochemistry to distinguish from other lesions with similar histology. This study explores the diagnostic utility of a panel of immunohistochemical markers and emphasizes potential pitfalls in dealing with this differential diagnosis. A tissue microarray with 1 mm tissue cores was constructed to include 21 CCRCC, 19 adrenocortical lesions, and 15 retroperitoneal or mediastinal paragangliomas.